3The original EMS field guide has grown into the most used reference guide in EMS history. This is the guide that EMS Magazine calls The original and still the best. The Twentieth Edition of the EMS Field Guide, ALS Version makes it easy for paramedics, nurses and physicians to look up their patients' medications, check drug doses, quickly interpret 12-Lead ECGs and much more! Like all of our field guides, this is the resource you'll use in class and take with you throughout your career in the field. All Informed professional field guides are 3x5, fit easily in your pocket, have color-coded tabs, and are water-resistant, alcohol-fast and durable.